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Discussion Starter #1
Hello everybody,

I'm currently using a Torker II intake (starts at 2500 RPM to 6500) thats on top of a 455 with a comp cam that starts at 2500 RPM's, 2600 stall, 750 holley, stock 6x-8 heads, stock bottom end I have 373 gears. I'm more interested in 1/4 mile times.

I have two friends that are telling me to get different intakes.

1. Says get an offenhauser 360 dual plane intake which is idle to 6500. He says I should see a big difference.

2. My other friend says to get the Performer RPM which is also a dual plane and starts at 1500 RPM to 6500.

They both claim that this will increase low end torque and HP. Any thoughts on if changing the intake would help my 1/4 times?

Also spoke to the tech at summit and they said that I should get a 3000 stall and 411 gears which would help me out in the quarter more.
 

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between the two Id say the RPM, my choice would be a weiand stealth... and yes you should see a noticeable difference....

I also agree with the gear, I dont feel you need more stall with a dual plane, with the gear and a good intake (such as the RPM or my choice the stealth you will have quite the torque monster imo....


2wld4u:thumbup:
 

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2wld4u said:
.... my choice would be a weiand stealth...

2wld4u:thumbup:



I know it wasn't one of your options but I would pick the weiand stealth as well.


Judging by your username this 455 might be in a 76 grand prix, is the car modified externally and do you have pictures? Just qurious, I used to have a 77 grand prix years ago and wanted to modify it just because it was different but never did.
 

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Depending on what kind of cam your using I'd go for the Performer RPM if you want to stay with the 750. Otherwise I would recommend a stock intake from a 68-72 Pontiac engine with a Q-jet. As far as gears I'd stay with the 3.73 as 4.11's are alittle steep for a 455 with stock 6X heads. The 455 is a high torque low rpm engine and unless you have done alot of work to prep the rods and rod bolts for high rpm use you should try to keep the rpm's at a max of 5500. Either of the afore mentioned intakes will show a tremendous increase in throttle response along with bottom and mid range power. If you are running this engine in a heavy car such as a 76 Grand Prix you need the lower rpm torque. I recently switched from a Torker to a stock iron on the 400 in my GTO and it's a much stronger engine than before but I haven't gotten the bugs worked out of my Q-jet yet so I'm still using an 800 double pump spreadbore Holley on it. More throttle response and better mid range that I had with the Torker.
 

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If you have a 750 DP I would probably stick with the Torker II. The 750 DPs have downleg boosters. Downleg boosters don't work as well with a dual plane intake. You will loose a ton of bottom end with downlegs and a dual plane. For some reason the single plane intakes make better bottom end with them.

If you were to go with a 3310, the 750 vacuum carb, I would recommend the RPM intake. The vacuum carb came with the straight boosters. The 750 vacuum secondary carb can also potentially flow more air than the 750 DP. Check the Holley site. The 3310 has bigger venturis.

A 455 is a good bottom end torque engine. Build it for torque not upper RPM hp.
 

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i read an article in chevy high performance a couple mths.ago by kEVIN McCLELLAND in the q&a section.some guy wrote in and was describing the his future project and it included a torker 2 with a spacer.kevin is with flowmaster now but at the time of developement of the torker 2 he was with edelbrock and was part of the whole torker power project.anyway he said do not put a spacer on it as it was designed specifically for use w/o a spacer and aspacer would hurt performance.also he said it was made for power to 400 h.p. which was alot in those days.you need an rpm air gap or a victor jr.i have an original torker with 2" spacer and works well with 406 but i believe it would work better with a victor jr. or equivalent.a have a full size van and the torker has no trouble pulling the bottom end at all.good luck
 

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Ok, people are tell you that you need to change parts but you haven't spoke of any problems. If you're happy with it don't let others make you fix something that not broke. The correct gear are going to depend on the tire size as well as everything else. Personally I have never like the torkerII's.
Now if there is a problem let us know what's happening and give more info including your cam specs and maybe somebody can help you work it out.
 

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The main thing here to remember that he is working on a Pontiac and Pontiac 455's are very different as far as breathing and tuning than what works on the typical small block Chevy does not apply to the Pontiac. Depending on what 6X heads he's running on the 455 has a large effect on what his compression ratio is and what cam he's running also has an effect. Unless it's an all out race engine stay away from single plane intakes on 455 Pontiacs as most don't have the rpm capability for this style of intake to be effective. If it's had extensive head porting and has the proper compression ratio and has been thought out right the RPM is the better intake to use but if not then the better setup is a 68-72 stock iron intake with a Q-jet. This will net better performance and quicker times at the track. As I said before 4.11's are to steep a gear for a 455, in fact the 455 will perform much better with 3.55's than it will the 3.73's as 3.55's will keep it in the torque band longer and not overrev the engine. If you intend on staying with 3.73's at the track then you'll need 30 inch tall tires to keep from pushing the 455 out of it's intended range. Most of the fast running 455's on the street are primarily conservative engines with moderate compression ratios ( between 9.0-9.7:1) and most put out around 500 or more ft lbs of torque with what most would consider mild cams and most are running high to mid 12's and are fully streetable.
 

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Gone, seeing as the 455 is a low rpm engine he will not benifit at all using a single plane intake as he said he is running stock heads and bottom end so the rpm potential to utilize a single plane is not there. I tried using a single plane Torker on a 455 several years ago and the engine didn't perform at all, especially if I would've had the same gearing behind my 400 as I had behind the 455 the 455 wasn't any faster. If I would 've went to a stock intake I could have picked up as much two tenths or possibly more in the quarter. If he is running 6X-8 heads then he only has a compression ratio of around 8.4:1, but if he running 6X-4's then he has a compression ratio of around 9.6:1. A single plane intake on a 455 Pontiac is usless unless it's an all out race engine i.e. prepped crank, rods, custom pistons, balancing, fully worked heads (iron or aluminum) high ratio roller rockers, roller cam, fully prepped carb and ignition. Then you would benifit using a single plane on a 455 as then engine is set up to turn rpm's in excess of 6500 otherwise the 455 should be kept to a maximum of 5500 if it has been put together right and this where the stock iron 68-72 intake will out shine any single plane out there. Plus the single plane doesn't have the bottom end torque potential that the 455 benifits from, nor the mid range. This is where the stock or the RPM will out perform the single plane hands down, and will provide quicker times in the quarter.
 

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Discussion Starter #12
Thank you all for your great advise...

Just to throw in the carb I'm using is a 3310, 750 vacuum carb. I will take a closer look at the "Stealth" Intake and compare that with the RPM Performer.

Well since I'm changing out my intake, I noticed a lifter noise. I'm going to change them out too. I was thinking of going with Rhoads lifters any thoughts on that too?

For those of you interested the engine is in a 1976 Grand Prix and pictures, and videos can be seen at www.speedfiend.com
 

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Grand Prix 76 what 6X heads do you have, 4's or 8's? Also what are your cam specs? If you really want to get your 455 to really perform then your better off with a dual plane. As far as Rhodes lifters it depends on what cam you have and what heads your using so I can determine exactly what compression ratio your engine has.

Grand Prix 76 I just checked out Holleys site and checked out the Weiand intakes and there is not a Stealth made for a Pontiac, just a dual plane that will not clear an HEI distributor. Like I said in my previous posts let me know exactly what has been done ot the engine and what heads your using and I can put you on a setup that will make your 455 a beast.
 

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Discussion Starter #17 (Edited)
The heads are 6x 8 heads. The cam is the following:

Comp Cam

Duration 244/244
Lift 501/501
RPM Range 2500/6500

Heads are stock besides 3 angle valve job and stiffer springs.

Bottom has stock internals. The only thing that has changed is the top end, cam, intake, carb, and headers, along with the 373 gears and 2600 stall. Hope this help
 

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Yes it helps as you only have around 8.2:1 compression and a cam designed for a minimum of 9.75:1 compression. In other words to much cam for your engine. Even as good as Rhodes Lifters are they won't even let enough cylinder pressure bleed off for you to run this cam effectively. Unless you want to find some better heads such as 6X4's or 96's you would be better of with a Performer intake and a milder cam such as the Summit 2801. This combination will make your 455 stronger and let you take advantage of the 455's torque potential. Right now you'd be lucky to turn times in the eighth in the mid nines. I.E. a friend of mine had a simular set up to yours in a 74 GTO ( about 500-600 lbs lighter than your GP) 455, .480 Comp cam, 4X heads, 3 angle ported and polished, 750 Holley, headers, RPM intake 4speed and 3.73 gears. His best time was an 8.50 and what really made him sick was the fact that my 71 GTO with a stock 400, Ram Air IV cam headers, 670 heads and 650 spreadbore Holley with a 4 speed and 3.55 rearend was running 8.56-8.52 in the eighth, and that was with a Performer intake. The reason a better thought out combination and the right compression for the cam, and he was 300 lbs lighter than my 71. The reason to much cam for an 8.5 compression engine plus to steep a rear gear, not letting the 455 stay in it's torque band. I have owned my GTO now for 18 years and just switched from a Torker intake to a stock iron and I'm running a 00071 Lunati BracketmasterII cam (.490 lift- [email protected]) Third to fourth shifts now at 5600 will literally tear my head off, never had that kind of kick with the Torker and this is with the same 800 Holley spreadbore sitting on top. Hope to get to the track in the next couple of weeks and feel confident that 8.20's are within easy reach. Also much stronger in the mid range than it was with the Torker and throttle response is much better. In fact these questions come up quite often on a Pontiac Forum I belong to and like you most have overcammed their engines with such low compression and the Summit cam is one of the most recommended for a car such as yours. Why don't you present the same question on the tech forum at Performance Years website and see if the responses you get are the same as mine. www.perfomanceyears.com.
 

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Discussion Starter #20
Well thank you for all the information...and glad to have so much feed back from the group.

So you say I should get the summit cam and run with the Performer RPM intake then?
 
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